1. Field:
The present disclosure relates generally to aircraft and, in particular, to a method and apparatus for testing hardware units of the aircraft. Still more particularly, the present disclosure relates to a method and apparatus for testing timing requirements of software on controller units of the aircraft.
2. Background:
Aircraft may have an electrical power generating and start system. The system may generate and control the electrical power on the aircraft. The system may also provide the auxiliary power unit and main engine start capabilities. The system may also drive the cabin air compressors and electric motor pumps. The system may comprise common motor starter controllers.
The common motor starter controller may control and monitor the state of the power system. The common motor starter controller may start the auxiliary power unit and other motors of the aircraft. The common motor starter controller may also monitor voltages for spikes and then shut down that particular system if there is a spike. If any signals being monitored violate expected values, then corrective action must be taken. Monitoring is done to protect hardware of an aircraft, such as, the common motor starter controller itself, the actual motor being started, or wiring within the aircraft. If a current gets too high in the wiring, the motor or wiring may fail. Relatively tight timing requirements exist that define when the monitor should result in corrective action.
Due to the tight timing requirements, the timing requirements of the common motor starter controllers may be one area that is tested specifically. Common motor starter controllers may be tested prior to use. Testing may be done on the timing of the embedded software on the controller.
For example, given that a current exceeding 100 amperes for more than 10 milliseconds is not an acceptable spike in current, the common motor starter controller may need to cut off all current to the motor. If the current exceeds 100 amperes for only 9 milliseconds then this may be an acceptable spike. Tests may be written to verify that a spike of 99 amperes, a spike of 100 amperes for 10 milliseconds, and a spike of over 100 amperes for 9 milliseconds does not cut off the current to the motor.
The tests may be run in hardware labs with expensive test equipments to collect actual measurements. Most of the data collected with the test equipments may be manually analyzed. One timing requirement, such as the one discussed above, may require test cases. Hundreds to thousands of timing requirements may exist requiring many types of lab equipment, time, and cost.
Therefore, it would be advantageous to have a method and apparatus that takes into account one or more of the issues discussed above.